Cruise is best known for creating an aftermarket kit that allowed owners of Audi A4 and S4 cars to turn them into autonomous vehicles. Those kits didn’t allow for full automation, though; they were meant for highway driving.

GM told Fortune it planned to grow its new company aggressively, and that Cruise will operate independently within GM.

Location likely figured into the deal as well. Other major car manufacturers like Ford have Bay Area-based R&D facilities, and the efforts of Google and (maybe) Apple with autonomous driving are based in Silicon Valley.

GM is also edging into on-demand ride hailing services with Maven, which may have spurred its initial interest in investing in Cruise. Unfortunately, GM isn’t even hinting at what it wants to do with Cruise, so we’ll have to wait and see.